Astroblog

Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Monday, November 29, 2010

The Sky This Week - Thursday December 2 to Thursday December 9

The New Moon is Monday December 6. Mercury meets the Moon Dec 7. Jupiter is easily seen in the evening sky. Venus visible together with Saturn and the crescent Moon in the morning sky. Comet 103P Hartley in amongst open clusters. The variable star Mira dims.

Morning sky looking east as seen from Adelaide at 5:00 am daylight saving time on Thursday December 3 showing Saturn, Venus and the crescent Moon . Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The New Moon is Monday December 6.

Bright white Venus continues to rise above the eastern morning horizon and is now readily seen in the early morning sky. Venus, Saturn and the bright star Spica form a line in the morning sky and on Friday the 3rd the crescent Moon visits Venus.

Saturn, Spica and Venus make an attractive morning sight. Saturn is almost high enough for telescopic observation.

Evening sky looking west showing the Mars and Mercury at 9:00 pm local daylight saving time on Tuesday December 7. Click to embiggen.

Mercury is climbing higher in the evening sky and now is reasonably easy to see in the late twilight. On Tuesday December 7 Mercury and the thin, day old crescent Moon are close.

Mars is now very difficult to see, low in the twilight below Mercury.

Jupiter rises before sunset, and can be readily seen from about 7:00 pm local time. Jupiter now spends most of the evening above the northern horizon.

Jupiter is excellent in binoculars and small telescopes.

Jupiter and Uranus are still close together and can be seen near each other in a pair of binoculars, although they are just in binocular range. Jupiter and Uranus come closer to each other this week. Uranus is the brightest object within a binocular field north of Jupiter, and is in fact bright enough to be (just) seen with the unaided eye under dark sky conditions. A binocular spotters map is here.

Jupiter's Moons are always interesting, in binoculars or telescopes of any size. There are lots of opportunities to see cool Jupiter Moon events (scroll down until you hit Jupiter).

The variable star Mira is still bright. You can watch Mira fade over the coming week, before Moonlight interferes.

Comet 103P Hartley above the northern horizon at midnight ACDST (11 pm non-daylight saving time) as seen from Adelaide on December 5, similar views will be seen from other places at equivalent local time.

Comet 103P Hartley 2 continues to rise higher in the southern skies. It is very high in the sky near Canis major and Sirius. The comet is fading, and this is probably the last week it will be visible in binoculars.

The comet is rising earlier, and with the Moon close to new setting later this means you do not have to get up quite so early in the morning to see it (after midnight is better though when it is higher in the sky). This week the comet will remain in binocular range of a number of beautiful open clusters, including the delightful M47 and M46. This is best viewed with binoculars or a small telescope. Although the comet is reasonably bright, its diffuse nature means it will be a challenge to see in binoculars, except under very dark skies.

Sunday, November 28, 2010

Jupiter's Belt to Return?

In case you didn't know, one of Jupiter's belts was missing. I didn't know until September, when I started imaging Jupiter again. I thought something was rather odd, the familiar double bands that I has seen for years was gone, replaced by a single band.

The image to the left contrasts the view through Don, my 8" Newtonian, on August 2009 and September 2010, at similar parts of it's opposition cycle (imaged with a Pillips ToUCam). As you can see the distinctive southern band is now a pale and anemic band (but it's now much easier to see the Great Red Spot).

We all know that Jupiter's atmosphere is very dynamic, but for an entire band to go is ridiculous! As it happens this event has occurred several times in the past. What astronomers thing is happening is that high white clouds of ammonia ice are forming above the darker band, obscuring it from view. Then, weeks to even years later, dark material erupts from below the cloud deck and the band reforms.

This image is a composite of three color images taken on Nov. 18, 2010, by the Gemini North telescope in Hawaii. The composite image shows a belt that had previously vanished in Jupiter's atmosphere is now reappearing. Image credit: NASA/JPL/UH/NIRI/Gemin

Recent infrared and optical imaging shows material appearing above the ammonia clouds in the past few days, and it looks like Jupiter is getting it's southern equatorial belt back. So now is a good time for amateurs to watch our giant planet, as the reappearance of the belt should make for some interesting viewing (if the cloud ever clears for me, I'll be watching too).

Emily Lakdawalla has some great explanations and images, as well as animations, here. The Bad Astronomer has a good discussion as well.

Friday, November 26, 2010

Framing the Image

Chart of Comet 103P near Mel 71 visualized in SkyMap, the rectangle is the approximate size of the global-rent-a-scope G14 instrument's CCD imager field of view (155.8 x 233.7 arc minutes) drawn with SkyMaps CCD frame tool. Click to embiggen.

If you are new to astronomical imaging, there are a few tricks that can make your life easier. One of these is being able to work out the orientation of the imaging camera’s (CCD device) field of view. For many objects, we don’t particularly care. The object is centered in the field of view and so long as it is not to big (so that it overflows the imaging space) it will be fine.

But if you want to make a mosaic of an object over a larger area, or if you want to image two interesting objects which aren't close to the center of the FOV, then the orientation of the CCD imaging device is important.

Image of comet 103P Hartley near Mel 71 taken with the global-rent-a-scope G14 instrument, click to embiggen to compare the chart above with the actual image.

If the CCD imager is square, like the STEREO spacecraft's H1A imager, no problem, but if the imager is significantly rectangular, like the GRAS 14 instrument at Global Rent a Scope which has a field of view (FOV) of 155.8 x 233.7 arc minutes, or my Philips ToUCam webcam (roughly 20x 10 arc minutes) then you have to be aware of the orientation of the FOV, or your image won't include what you want.

With my web cam it's fairly simple, I can just grab it and rotate it until I have the desired FOV orientation (and since I almost always do planetary imaging with it and have live preview, this is fairly easy to do, except when I was imaging Vesta). With remote scopes it's a bit trial and error, and you may have to do a trial shot to see which way the CCD FOV is oriented. For example, with global-rent-a-scope the imager G14 FOV long axis is oriented North-South, while the G5 imager FOV long axis is oriented East-West (with regard to the star chart orientation, see chart and image above).

Useful information, but what to do with it? Well, all decent planetarium programs can place CCD frame outlines on the maps they have drawn (for example, in SkyMap the CCD frame tool is in the Insert | Camera/CCD frame menu item, in the freeware Cartes du Ciel it's Chart | Lines / Grid | Show Mark). Most will have predefined frames, but will also allow you to draw your own CCD frames. In SkyMap I've created my own frames fo the STEREO H1A imager, my webcam and GRAS12 and GRAS5. For SkyMap you have to convert the arcminute FOV widths in the GRAS website to degrees, minutes and seconds if you are using the GRAS scopes.

All you have to do is get the program to draw the frame for you, and now you can work out what to image.

Well, not quite. There's a few quirks along the way which you have to watch out for. In SkyMap for instance, if you have the screen in RA/Dec mode, the frames will be in the correct orientation for G5, but wrong for G12. To get frames in line for G12, you have to labouriously hand rotate the screen so that the North-South axis runs left-right, then the first frame you put down will have the correct orientation (all subsequent ones will be in the WRONG orientation though, unless you revert to RA/Dec mode, then the subsequent frames follow the first frame orientation ... don't ask me why).

Thursday, November 25, 2010

Comet 103P/Hartley near Mel 71

Comet 103P Hartley near the open cluster Mel 71 on November 23, The image immediate left is a cropped shot from Global Rent a Scope GRAS-05 (click to embiggen).

Despite strong Moonlight I think it came out rather well.

The image is a stack of 3 x 30 second images with dark frame subtraction stacked in Image J using Z projection of maximum intensity and a lot of contrast fiddling. I still can't work out how to subtract flatfields correctly though.

This is a widefield image of the same area in GRAS 14. This is a colour series stacked in Image J using its colour series module.

The colour is pretty rubbish (but hey, I'm red-green colour blind), but you can clearly see the comet near Mel 71, Mel 72 off on the right hand side of the image and NGC2423 off to the left. You definitely need to click to embiggen this one.

I have no idea why the colour is so weird here, my previous colour shots have been fine. Well, I have the originals to play around with.

I still have a whole bunch of 103P images to post, and lots of 103P news as well (and 2010 V1 image links). The comet is going to be in spectacular territory in the next few days, but strong Moonlight is a problem.

Carnival of Space #178 is here.

Carnival of Space #178 is now up at We Are All In The Gutter. There's zombie microbes and the search for life on Mars, Buzz Aldrin on colonizing Mars, rocket propelled Mars rovers, Hyabusa's successful asteroid dust return and much much more. Strap your jetpack on and zoom on over.

Tuesday, November 23, 2010

Comet 43P Harrington near NGC 4094

This was going to be a bit of a challenge, 43P is a dim, 14.5 magnitude comet. At astronomical twilight it was only 25 degrees above the horizon, just within range of the GRAS scopes and clearing away from the horizon murk.

The image is a stack of 2 x 90 second frames (after dark frame correction), converted to a single image using Z projection of MAX intensity. It should have been 3 but the scope lost tracking on the last image.

Still, I think it came out rather well, more images to stack would have been better, but the time frame was tight.

The Sky This Week - Thursday November 25 to Thursday December 2

The Last Quarter Moon is Monday November 29. Mercury climbs the Scorpion and leaves Mars. Jupiter is easily seen in the evening sky. Venus visible together with Saturn and the crescent Moon in the morning sky. Comet 103P Hartley in amongst open clusters. The variable star Mira dims.

Morning sky looking east as seen from Adelaide at 5:00 am daylight saving time on Thursday December 2 showing Saturn, the crescent Moon and Venus. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The Last Quarter Moon is Monday November 29.

Bright white Venus continues to rise above the eastern morning horizon and is now readily seen in the early morning sky. Venus, Saturn and the bright star Spica form a line in the morning sky and on Thursday the 2nd the crescent Moon visits Saturn.

Evening sky looking west showing the Mars and Mercury at 9:00 pm local daylight saving time on Sunday November 28. Click to embiggen.

Mercury is climbing higher in the evening sky and now is reasonably easy to see in the late twilight. Mercury continues to climbs the Scorpion, leaving Mars behind to sink in the twilight.

Mars is now very difficult to see, low in the twilight below Mercury.

Jupiter rises before sunset, and can be readily seen from about 7:00 pm local time. Jupiter now spends most of the evening above the northern horizon.

Jupiter is excellent in binoculars and small telescopes.

Jupiter and Uranus are still close together and can be seen near each other in a pair of binoculars, although they are just in binocular range. Uranus is the brightest object within a binocular field north of Jupiter, and is in fact bright enough to be (just) seen with the unaided eye under dark sky conditions. A binocular spotters map is here.

Jupiter's Moons are always interesting, in binoculars or telescopes of any size. There are lots of opportunities to see cool Jupiter Moon events (scroll down until you hit Jupiter).

The variable star Mira is still bright. With the Moon rising later, you can watch Mira fade over the coming weeks.

Comet 103P Hartley above the northern horizon at midnight ACDST (11 pm non-daylight saving time) as seen from Adelaide on November 28, similar views will be seen from other places at equivalent local time.

Comet 103P Hartley 2 continues to rise higher in the southern skies. It is very high in the sky heading towards Canis major and Sirius, although the comet is fading, it is still visible in binoculars.

The comet is rising earlier, and with the Moon setting later this means you do not have to get up quite so early in the morning to see it (after midnight is better though when it is higher in the sky). Between the 28th and the 2nd the comet will be in the heart of a number of beautiful open clusters, including the delightful M47 and M46. This is best viewed with binoculars or a small telescope. Although the comet is reasonably bright, its diffuse nature means it will be a bit of a challenge to see in binoculars

Sunday, November 21, 2010

The ISS and Parallax, One More Time

After our attempt to use parallax to determine the height of an iridium flare, Dean Male and I tried to do it with an ISS pass, somewhat higher in the sky to fix some issues with the parallax calculations. I got the ISS as it was at its highest, but Deans firing mechanism had a meltdown and his shots might not be salvageable.

Oh well, there's next time.

The left image is the ISS above Iota Grus at 21:15:35, Canon IXUS, 400 ASA, 15 second exposure. The bottom image is the ISS passing the bright star Canopus a few minutes later

Mobile Phone ISS

The ISS about to glide over the top of the Moon, taken with a mobile phone on "night time" setting.The reddish dot lower left is a camera artefact, the ISS is the bright dot immediately to the left of the Moon.

On Saturday night the ISS was due to pass over the Moon, but Saturday saw us helping Kyack Cousin clean up, then we went to the Port Adelaide Christmas pageant. After the pageant we hung out at the kids concert and then went to get a burger at the Port Dock Hotel.

Along with almost everyone else in the Port. An hour later our burgers hadn't arrived and the time for the ISS pass was almost up. At least we got to watch the Morris dancers while we waited. Of course, I didn't bring my camera, because we were going to be well home (sigh). But I did have my mobile, so I wandered over to a convenient...um, squarish metal thing and set up.

The ISS did it's thing, and I got several shots with the mobile phone. As you can see they came out reasonably well, except of the one with the ISS directly over the Moon, I moved when taking that. So you can use your mobile phones for satellite imagery as well.

I pointed out the pass to the kids and the people at adjoining tables, who were suitably impressed.

Then the burgers arrived.By the time we finished them off we were able to enjoy the fireworks, so everything worked out okay.

Friday, November 19, 2010

Global Warming Updated

Over on the discussion list I'm on, Science Matters, a "discussion" has broken out about global warming. A correspondent has posted an graph of satellite data claiming thata) the satellite records are more reliable than ground recordsb) the "trendlines" show the world is cooling andc) the dip cannot be explained as a statistical anomaly.

Unfortunately for our correspondent, the data he showed ended in 2008, and there is much more recent data that falsifies his claims. The graph on the left is the most recent satellite data from the University of Alabama at Hunstville (UAH lower troposphere data here, middle troposphere data here).

I've plotted the raw data (dots), the linear fit (black line), the 5 year rolling average (red line) and a polynomial fit (colour I can't describe because I'm red-green colour blind). I've also done the same plot with one year averages, rather than raw data (here the polynomial fit is the blue line). You can click on all images to embiggen.

You can see immediately that the temperature is not falling, but relentlessly increasing. Indeed the increase from the UAH satellite data (0.14 degrees per decade), is very similar to the ground based increase (0.18 degrees per decade) and the RSS satellite data (0.17 degrees per decade).

You can use the data plotter at Wood for the Trees to overlay the latest ground and satellite data, an overlay with trendlines is here.

I've also indicated on the raw data graph some major climatic events; volcanic eruptions (Pintabo, El Chichon) and El Nino and La Nina events. 2008 was a strong La Nina event which produced a temporary downswing. The downswing in 2008 was not a statistical blip, but a well understood temporary effect of the La Nina/El Nino phenomena. in contrast 2009 tied for the hottest year on record in the land based data set, and 2010 looks to be not far behind.

Left image, my plot of middle troposphere temperatures to October 2010, the blue line is the polynomial fit zooming upwards, right image, the plot of middle troposphere temperatures to mid 2008, the polynomial (NOT a trend), zooms down. This is why you don't trust polynomial fits

One amusing effect is what happens to the polynomial fit. The correspondent claimed the "trendline" showed a downward swing, but its a polynomial fit, not a trendline. As I've written before polynomial fits are very misleading, because they exaggerate end effects (see also here). With the most recent data, the polynomial fit skyrockets, by our correspondents logic, we are in for sustained catastrophic warming.

Image credit Real Climate. Showing how the satellite record of temperatures follows the surface temperatures.

As well, the correspondent sees satellite data as more reliable than surface station temperature records, the surface station records are infact pretty good. Satellite measurements have a wide variety of problems of their own, from reconciling different satellite instrumentation, to changing orbits, to instrumental calibration to the fact the sensors peer through a cooling stratosphere. This compendious (and very large 145 page) paper gives a long list of the calibration problems and their attempted resolution.

The main points are that satellite data confirms the land based data and it's not "better".

Wednesday, November 17, 2010

Leonid Meteor Shower, Thursday November 18, 2010

Constellation of Leo as seen at 4:00 am daylight saving time 0n the morning of November 18. The Leonid radiant is near the centre of the sickle of Leo, just to the left of Regulus.

The Leonid Meteor shower is at its peak form the point of view of Australian's on the morning of Thursday 18 November (17 November UT). The best time to observe is between 3 and 4 am (daylight saving time, 2-3 am non-daylight saving time).

Despite the sky being Moon-free when Leo rises there will be very few Leonids seen from Australia, maybe 2-3 per hour.

You can check predictions for you local site with the NASA meteor flux estimator (scroll down to 13 Leonids in the SHOWER box, make sure you have your location and date correct as well).

If you are up that early anyway, looking at comet 103P Hartley, look to the east, you may see a couple of interesting meteors, but nothing spectacular.

When you get up, allow at least 5 minutes for your eyes to adjust, and be patient, it may be several minutes before you are rewarded with you first meteor, then a couple will come along in quick succession. Choose a viewing spot where you can see a large swathe of sky without trees or buildings getting in the way, or with streetlights getting in your eyes. The darker the spot the better (but do be sensible, don't choose a spot in an unsalubrious park for example).

A lawn chair or something similar will make your observing comfortable (or a picnic rug spread on the ground and a nice pillow), and having a thermos of hot coffee, tea or chocolate to swig while watching will increase your comfort. (Here's some hints on dark adaption of your eyes so you can see meteors better). Don't look exactly at the radiant spot, but look a bit to one side.

The meteors may be disappointing, but with binoculars you can see a (very dim) comet, the skuy is beautiful and Saun and Venus will rise towards the end of observing time. So you will still have a nice time.

I Spoke to MiddleOnes Class about Astronomy...

Jupiter near the Moon, as seen from my suburb at 11:30 pm daylight saving time.

...and it was terrific! The kids were amazing and I had so much fun!

MiddleOnes class has been doing space and the solar system, and as geeky astronomy dad I was invited to talk to them about space. I revised my talk about using the Moon to guide you to the planets that I gave to the Bellevue Heights Junior Field Naturalists Club.

For one thing, the kids were older (11-12), and as I said they had been doing space in class, so I had to give a more advanced perspective. I updated and upgraded my powerpoint and I completely revised my Celestia and Stellarium scripts (I have to add a time command to the Celestia script so that dactyl doesn't drift out of the field of view). I printed out a handout with a star map and the times when the Moon would be near bright planets. This time round I was able to use Stellarium to illustrate how to use the star maps (these things are not intuitive).

But as I said, the kids were fantastic. Enthusiastic, perceptive and asking really good questions. The questions ranged from what caused the tides, to what the Moon looked like 3.5 billion years ago, to what caused Enceladus geysers, to what is inside a black hole. I got to use my tour of exoplanet skies script. One student even had heard of the newly discovered baby black hole! Now that is switched on, I only wish my University students were as enthusiastic. I could have talked until my voice gave out.

Maybe in a few years time these kids will be solving mysteries of the Solar System, or discovering comets. But tonight, at least, some of them will be looking at the skies with fresh eyes.

I've put up the updated scripts for you to download and play with (waves to MiddleOnes class mates if any are reading this); download Moons.cel and put it in your Celestia folder, then use File | Open Script to run it. Download The Moon Guide and put it in scripts folder (unfortunately, it's version 0.9 script, I'll translate it to 1.05 later). If you don't have the free programs Celestia and Stellarium you can download them from the links (Kids, ask you parents/guardians first before downloading stuff).

The Sky This Week - Thursday November 18 to Thursday November 25

The Full Moon is Monday November 22. Mercury climbs the Scorpion and meets Mars. Jupiter is easily seen in the evening sky. Venus visible together with Saturn in the morning sky. Leonid meteor shower on the morning of the 18th will be disappointing. Comet 103P Hartley heads for a mass of open clusters. The variable star Mira is brighter.

Morning sky looking east as seen from Adelaide at 5:00 am daylight saving time on Sunday November 21 showing Saturn and Venus. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The Full Moon is Monday November 22.

Bright white Venus continues to rise above the eastern morning horizon. At the begining of the week you will still need a fairly level, uncluttered horizon to see it. By the end of the week it should be easy to see from almost anywhere. Venus, Saturn and the bright star Spica form a line in the morning sky.

Saturn becomes easier to see in the morning as it rises higher in the twilight. By the end of the week the trio of Saturn, Spica and Venus will make an attractive morning sight.

Evening sky looking west showing the Mars and Mercury at 8:45 pm local daylight saving time on Sunday November 21. Click to embiggen.

Mercury is climbing higher in the evening sky but will still not be very high, although it is much easier to see than last week. Like Mars before it, Mercury climbs the Scorpion and Mercury, Mars and Antares make a nice line. On the 21st Mercury and Mars are at their closest.

Mars is becoming harder to see in the twilight. It is the third brightest object above the western horizon, after the red star Antares (which means Rival of Mars) and Mercury. After this weeks encounter with Mercury, Mars sinks lower into the twilight.

Jupiter rises before sunset, and can be readily seen from about 7:00 pm local time. Jupiter now spends most of the evening above the northern horizon.

Jupiter was at opposition well over a month ago, when it was at its biggest and brightest as seen from Earth. However, Jupiter will still be excellent in binoculars and small telescopes for many weeks to come.

Jupiter and Uranus are still close together and can be seen near each other in a pair of binoculars, although they are just in binocular range. Uranus is the brightest object within a binocular field north of Jupiter, and is in fact bright enough to be (just) seen with the unaided eye under dark sky conditions. A binocular spotters map is here.

Jupiter's Moons are always interesting, in binoculars or telescopes of any size. There are lots of opportunities to see cool Jupiter Moon events (scroll down until you hit Jupiter).

The variable star Mira is still bright. this week the bright Moon will make it difficult to observe though.

The Leonid Meteor shower is at its peak on the morning of Thursday 18 November (17 November UT). Despite the sky being Moon free when Leo rises (3:00 am daylight saving time, best between 4-5 am daylight saving time), there will be very few Leonids seen from Australia, maybe 2-3 per hour. You can check predictions for you local site with the NASA meteor flux estimator (scroll down to 13 Leonids in the SHOWER box, make sure you have your location and date correct as well). If you are up that early anyway, looking at comet 103P Hartley, look to the east, you may see a couple of interesting meteors, but nothing spectacular.

Comet 103P Hartley above the northern horizon at 1:00 am ACDST (midnight non-daylight saving time) as seen from Adelaide on November 24 , similar views will be seen from other places at equivalent local time.

Comet 103P Hartley 2 continues to rise higher in the southern skies. It is very high in the sky heading towards Canis major and Sirius, although the comet is fading, it is still visible in binoculars binoculars.

While the comet is rising earlier, advancing Moonlight means you still have to get up early in the morning to see it (between midnight and 4:40 am). By the 24th the comet will be in binocular range of a number of beautiful open clusters, including the delightful M47.

Which is pretty strange, the usual tack is to argue for Geocentrism based of relativistic frame equivalence. Arguing against relativity is pretty hard, as it is one of the best confirmed theories of physics we have. From gravitational lensing (see images above) to frame dragging, relativity has passed increasingly stringent tests with flying colours.

Now there is a lot of problems with this (not the least because they need a non-moving ether to explain the M-M experiment, then a moving ether to explain Foucault's Pendulum) and other geocentrist positions. Some of the problems can be demonstrated with intensive mathematics, some with not so much maths (like the claim that GPS doesn't use relativistic corrections, which is untrue.)

However, in the spirit of my first post on this conference, where I tried to get people to do observations themselves that disproved first the Ptolemaic then the Tychonian systems, I want to get people to do something much simpler, related to observational astronomy.

Also in the spirit of Einstein, who tried to imagine what the word would look like if you were travelling on a photon, I want you to imagine your are standing on Mars.

The evening sky on Mars on April 29, 2005 as simulated by Stellarium (the location isn't at the same latitude and longitude as opportunity, so the view is slightly different from the rover).

What would you see from the surface of Mars that would be different in a Tychonian system (the system favoured by our modern geocentricists) versus a heliocentric system system?

As the Tychonican system is an inverted Copernican system, things like the phases of the Earth would be identical (see this JAVAscript model, advance the time to October 3, 2007 to match the image of crescent Earth and Moon above, and flip between the Tychonian and Heliocentric models to see what I mean).

Earth imaged by the panoramic camera of Opportunity an hour after Sunset on April 29, 2005 (Image Credit NASA/JPL).

There is a big difference that would be immediately apparent. Whether in the Tychonian or Heliocentric systems, from the point of view from Mars, Earth would appear to be a morning or evening star that appeared to revolve around the Sun.

However, the geocentricists are using a geostationary model, where the 24 hour day is produced by the Sun rotating about the Earth. So in a period of 24 hours, an observer on Mars (armed with an occultation disk) would see Earth rise from the sun, then fall back, then reappear on the other side of the sun and repeat the process again.

During the period that the Mars rovers took images of the Earth, at maximum elongation Earth was 42-47 degrees from the Sun as seen from Mars. For the Earth to move from maximum elongation to inferior or superior conjunction (at least, as it would appear from Mars, because in the Tychonian system Earth can't have conjunctions) takes 6 hours (in a 24 hour day there will be four 6 hour segments as the Earth goes out, comes back, goes out and comes back again from the solar disk).

So the Earth will appear to move 42 degrees (taking the lowest figure) in 6 hours, or 7 degrees per hour against the background stars (approximately, it's slightly more complicated than this, but rough figures are all we need). That's 14 Lunar diameters per hour! Earth is fairly hooting along compared to the background stars. In one minute Earth would move 1/4 of a Lunar diameter which is quite noticeable.

Now look at the image above. It is a composite of 3 x 15 second images taken with the panoramic camera, you can see the image of Earth is slightly elongated. However, remember that Mars rotates, and any 15 second exposure will cause slight star trailing due to its rotation. The trail we see of Earth is nothing like what we would expect if it was moving to a 24 hour rhythm, as it hares along the sky (roughly 1/5th of a Lunar diameter). Still, for confirmation we have to check Earth's movement against that of the background stars.

Fortunately, in the original image there is a background star just above Earth (it's best seen in the TIF file). It has the same degree of elongation that the Earth does. This falsifies the Tychonian system, thus the solar system is heliocentric.

So "Eppur si muove" because it um, doesn't move (with respect to the background stars as seen from Mars).

Friday, November 12, 2010

Meet Archie

Archie the Galah is the latest addition to the Chez Reynella family, joining Blizzard the bearded dragon (below).

SmallestOne had a birthday, he is a prime number years old. All the boys are now prime numbers old. The sum of their ages is also a prime number, the sum of the first and second digits of this prime number subtracted from MiddleOnes age, gives Smallest ones age. The sum of the digits of the square of Smallest ones age is OldestOne's age.

Tuesday, November 09, 2010

Web Conference on the Orign of Life

I'm trying to watch and listen to the NAI Workshop Without Walls on Molecular Paleontology and Resurrection: Rewinding the Tape of Life. However, I'm also making breakfast and getting kids ready for school. It's very interesting though.

If you are interested, the workshop is scheduled for 1pm-5pm EST on November 8, 9, and 10, 2010. A detailed agenda and other information is posted online at http://astrobiology.nasa.gov/nai/ool-www/ and you can register to join in there, everyone is welcome.

The Sky This Week - Thursday November 11 to Thursday November 18

The First Quarter Moon is Sunday November 14. Mars climbs the Scorpion. Jupiter is easily seen in the evening sky. Venus visible together in the morning sky. Comet 103P Hartley climbs higher in the sky. The variable star Mira is brighter.

Morning sky looking east as seen from Adelaide at 5:30 am daylight saving time on Sunday November 14 showing Saturn and Venus. Similar views will be seen elsewhere at the equivalent local time. Click to embiggen.

The First Quarter Moon is Sunday November 14.

Bright white Venus starts the week close to the eastern morning horizon, so you will need a fairly level, uncluttered horizon to see it. During the week it rises higher in the sky and comes closer to the bright white star Spica.

Saturn becomes easier to see in the morning as it rises higher in the twilight. By the end of the week the trio of Saturn, Spica and Venus will make an attractive morning sight. The newly discovered comet 2010 V1 is close to Saturn at the beginning of the week (but you will need strong binoculars and dark skies to see it)

Evening sky looking west showing the Mars and Mercury at 8:30 pm local daylight saving time on Saturday November 13. Click to embiggen.

Mercury is climbing higher in the evening sky but you will need a clear level horizon to see it. On the 13th the Mercury and Mars from a triangle with the red star Antares. By the end of the week Mercury and Mars are close together.

Mars is becoming harder to see in the twilight. It is the third brightest object above the western horizon, after the red star Antares (which means Rival of Mars) and Mercury. During the week Mars draws closer to Antares and by the 13th they are closest.

Jupiter rises before sunset, and can be readily seen from about 7:00 pm local time. Jupiter now spends most of the evening above the northern horizon.

Jupiter was at opposition well over a month ago, when it was at its biggest and brightest as seen from Earth. However, Jupiter will still be excellent in binoculars and small telescopes for many weeks to come.

Jupiter and Uranus are still close together and can be seen near each other in a pair of binoculars, although they are just in binocular range. Uranus is the brightest object within a binocular field north of Jupiter, and is in fact bright enough to be (just) seen with the unaided eye under dark sky conditions. A binocular spotters map is here.

Jupiter's Moons are always interesting, in binoculars or telescopes of any size. There are lots of opportunities to see cool Jupiter Moon events (scroll down until you hit Jupiter).

The variable star Mira is very bright. You can follow it's changes in brightness when the Moon sets.

Comet 103P Hartley above the northern horizon at 2:30 am ACDST (1:30 non-daylight saving time) as seen from Adelaide on November 14 , similar views will be seen from other places at equivalent local time.

Comet 103P Hartley 2 rises higher in the southern skies this week. It is very high in the sky, above the bright star Procyon, but the comet is fading, and you now need binoculars to see it. And you do have to get up at dark o'clock to see it (between midnight and 4:40 am). The comet will be easily seen in binoculars, and it races through the sky through some pretty territory.

Monday, November 08, 2010

Moon, Mars and Antares

The 7% crescent Moon, Mars and ANtares from Largs North, Adelaide.

Came home from our Monday chess night with the Moon filled with Earth Shine and Mars glowing redly above the roofs of the neighbours. Yes, once again Blogger has put the image sideways (WHHYYY!!!!), Masr is bottom right above the antenna, Antares is centre bottom.

Why ...

Hartleyid Update

Despite a press release from the Center for Astrophysics suggesting they found Hartleyids (meteors from the dust trail of comet 103P Hartley), all the meteor observer lists have reported no Hartleyids in their observations. Looks like we didn't get any, which is a shame, we could have done with a new meteor shower.

There is some suggestion on the comet lists the 2010 V1 s like comet 17P. Links to ephemerides, spotters maps and Stellarium and Celestia files here. Links to ephemerides, spotters maps and Stellarium and Celestia files for 2010 V1 here.

Friday, November 05, 2010

A "Bright" New Comet in Virgo

Earth as seen from Comet C/2010 V1 (Ikeya-Murakami), visualized in Celestia (click to embiggen)

Congratulations to Kaoru Ikeya and Shigeki Murakami, two Japanese amateurs who have discovered a new comet by visual (telescopic) observation (Kaoru Ikeya has 7 comets to his name, so he's an experienced comet hunter).

The Comet, C/2010 V1 (Ikeya-Murakami), is in Virgo. At the moment it appears to be around 2 degrees from Saturn. According to some reports it’s between magnitude 8 and 9, which should be achievable in good binoculars. The best places to see the comet are sadly in the northern hemisphere. In the southern hemisphere it is too close to the horizon and the oncoming dawn to make out. Between the 25th and the 30th the comet is between Venus and Spica.

Location of Comet C/2010 V1 (Ikeya-Murakami) as seen from the Northern Hemisphere on the morning of November 5, an hour before sunrise (click to embiggen).

An image taken by Francois Kugel is here, and an image by Josep M. Aymami is here.

Here is a stellarium file for the comet (add to the end of the ssystem.ini file)

Here is the celestia file, but frustratingly it gives entirely the wrong position for the comet:==============================================================="Ikeya-Murakami:C/2010 V1" "Sol"{Class "comet"Mesh "borrelly.cms"Texture "asteroid.jpg"Radius 2.2